2024 How Much Does a Forklift Battery Cost
Table of Contents
- 2024 How Much Does a Forklift Battery Cost
- The Real Expense of Lead-Acid Forklift Batteries
- The Real Cost of Lithium Forklift Batteries
- How to Evaluate Whether Lithium-Ion is Right for Your Fleet
- Steps to Convert Your Forklift Fleet to Lithium Batteries
- Conclusion
- Six Important Parameters of Lithium Batteries
- 1. Battery capacity
- 2. Nominal voltage
- 3. Charge termination voltage
- 4. Discharge termination voltage
- 5. Internal resistance of the battery
- 6. Self-discharge rate
- Lithium battery PCM principle
- Composition and structure of lithium iron phosphate battery
Forklift battery cost varies depending on the type and size of the battery. For lead-acid forklift batteries, the cost ranges from $2,000 to $6,000. In contrast, a lithium forklift battery typically costs between $17,000 and $20,000. However, MANLY Battery offers a more affordable range, with lithium forklift battery prices starting from $250 for smaller forklifts to $7,500 for larger models (excluding additional fees). Despite the higher initial investment, lithium batteries provide long-term savings through reduced maintenance, quicker charging, and longer lifespans. In this section, we will outline the steps to convert your forklift fleet to lithium-ion technology and maximize the benefits of this switch.
The Real Expense of Lead-Acid Forklift Batteries
1. Cost of Lead-Acid Batteries Over Time
The initial cost of a lead acid forklift battery might seem appealing due to its lower upfront price compared to lithium alternatives. However, the real expense accumulates over time due to several factors related to performance, labor, and operational efficiency. Lead-acid batteries typically require extensive maintenance, including regular watering, equalizing charges, and frequent monitoring. These processes consume both time and resources.
Each lead acid forklift battery can only operate for about 8 hours before needing a recharge, which takes approximately 16 hours to fully charge and cool down. For warehouses that run 24-hour operations, this means each forklift needs at least three batteries to function continuously. Managing these batteries requires labor-intensive tasks, such as switching out batteries, monitoring charging cycles, and performing maintenance, which leads to increased labor costs over time. The need to frequently stop operations to change batteries also reduces overall productivity, making the long-term cost of lead-acid batteries higher than initially perceived.
Over time, forklift battery replacement becomes inevitable as lead-acid batteries lose efficiency after around 1500 charge cycles, which generally occurs every 2-3 years. This frequent replacement cycle, combined with the need for multiple batteries per forklift, drives up costs significantly compared to alternatives like lithium forklift batteries, which have much longer lifespans and quicker charging times.
2. Storage Costs of Lead-Acid Batteries
One often overlooked cost associated with lead acid forklift battery use is the storage requirement. Lead-acid batteries are large and bulky, and warehouses must dedicate considerable space for both storage and charging stations. These batteries need a specific area for safe charging and cooling, often referred to as the battery room, which must meet strict guidelines to ensure safety.
The battery storage area must have proper ventilation to manage the gases emitted during the charging process, as well as the necessary infrastructure to handle these heavy batteries. This involves installing equipment such as overhead cranes or battery transfer carts to move the batteries safely. In addition to the physical space required, warehouses must invest in specialized monitoring systems to track battery conditions, charging cycles, and maintenance needs, all of which increase operational costs.
The storage area cannot be repurposed for other productive uses, meaning that valuable warehouse space is taken up solely for battery management. Over time, the inefficiency in space usage contributes to increased costs, particularly for businesses looking to maximize their warehouse floor for inventory or other operational needs.
3. Occupational Hazards and Risks
The use of lead acid forklift batteries also introduces significant occupational hazards. These batteries contain corrosive sulfuric acid and lead, both of which pose serious risks to workers. If a battery leaks or spills, it can cause severe chemical burns or environmental contamination. Handling these batteries requires specialized safety equipment and training to avoid accidents, adding to the operational cost.
Moreover, during the charging process, lead-acid batteries emit hydrogen gas, which is highly flammable. This creates a potential explosion risk if the gas accumulates in an inadequately ventilated space. Battery charging areas must be equipped with proper ventilation systems and safety measures to mitigate these risks. Even with these precautions, the possibility of accidents remains, which can lead to costly downtime, medical expenses, and potential fines if workplace safety regulations are not strictly followed.
In addition to physical risks, the labor required to maintain lead-acid batteries is another source of long-term cost. Workers must regularly water the batteries, clean corrosion from the terminals, and ensure that they are properly charged and cooled. These maintenance tasks take time away from other productive activities, adding hidden costs to the overall expense of using lead-acid batteries.
4. Replacement Expenses for Lead-Acid Batteries
Forklift battery replacement is a recurring cost that companies using lead-acid batteries must factor into their long-term budgeting. As mentioned earlier, these batteries typically last around 1500 charging cycles, which translates to about 2-3 years of usage under normal conditions. After this period, they need to be replaced, and this can become quite expensive when managing a large fleet of forklifts.
Each lead acid forklift battery is a significant investment, and purchasing multiple batteries every few years adds up. The cost of disposal also needs to be considered, as lead-acid batteries contain hazardous materials that require proper handling and recycling. Failing to dispose of them correctly can result in fines or environmental penalties, adding to the overall expense.
In contrast, lithium forklift batteries offer a much longer lifespan, often lasting up to 5000 cycles, which significantly reduces the frequency of replacement. While the upfront cost of lithium batteries is higher, the long-term savings in replacement expenses, maintenance, and labor make them a more cost-effective option for many businesses.
The Real Cost of Lithium Forklift Batteries
1. Lithium Forklift Battery Cost
When comparing the costs of lithium forklift batteries to lead-acid alternatives, the upfront price is significantly higher. On average, a lithium forklift battery costs between $17,000 and $20,000, which is about 2 to 2.5 times the price of a comparable lead-acid battery. This higher initial cost can be a deterrent for some businesses, but it’s essential to consider the long-term savings that come with this investment.
The primary areas where lithium forklift batteries save costs include energy efficiency, reduced downtime, minimal maintenance, and longer lifespan. Lithium forklift batteries are about 30% more energy-efficient than lead-acid batteries, and they can charge up to eight times faster. This means less electricity is used to power the same amount of work, leading to noticeable savings on energy bills over time. Additionally, the ability to charge the battery during breaks ensures continuous operation, which eliminates the need for multiple batteries per forklift, reducing overall battery investment.
Moreover, lithium forklift batteries can last two to four times longer than lead-acid batteries, meaning fewer replacements are needed over the years. This extended lifespan reduces the total number of batteries that need to be purchased, stored, and maintained, which further lowers overall operational costs. Although the initial lithium forklift battery cost is higher, the total cost of ownership becomes more favorable as savings accumulate in energy, labor, and replacements.
In addition to the general price range of lithium forklift batteries, MANLY Battery offers a more accessible option for businesses of all sizes. MANLY’s lithium forklift battery range is priced between $250 and $7,500, depending on the forklift model and battery capacity. This competitive pricing ensures that companies looking to switch to lithium technology have a broader range of options, from smaller forklifts requiring less power to larger industrial models. MANLY Battery’s products maintain high performance and durability while offering a more cost-effective solution in the lithium forklift battery market, making it easier for businesses to transition without the steep initial investment often associated with lithium technology.
Table of MANLY lithium Forklift Battery Cost (Partial list):
| Model No. | Specification | Unit price (USD) | Notes |
| ≤200 | |||
| MLP24150M | Battery Type: LiFePO4 Nominal Voltage:25.6V; Rated Capacity: 150AH Steel Case; Dimension: 640*245*220mm Cycle life: 5,000+ times; Lifespan: 15+ years design |
$750.00 | EXW price per battery excludes additional fees |
| MLP36200M | Battery Type: LiFePO4 Nominal Voltage: 38.4V; Rated Capacity: 200AH Steel Case; Dimension: 560*520*180mm Cycle life: 5,000+ times; Lifespan: 15+ years design |
$1,500.00 | |
| MLP72420M | Battery Type: LiFePO4 Nominal Voltage: 73.6V; Rated Capacity: 420AH Steel Case; Dimension: 700*600*550mm Cycle life: 5,000+ times; Lifespan: 15+ years design |
$6,000.00 |
Want more details or other models? Contact our customer service today!
2. Lithium Ion Forklift Battery Safety
One of the most significant advantages of lithium ion forklift batteries is their superior safety compared to lead-acid batteries. Lead-acid batteries require regular maintenance, including watering and acid handling, which exposes workers to hazardous chemicals like sulfuric acid. These batteries also emit hydrogen gas during charging, which can create an explosion risk if not properly ventilated. Furthermore, the risk of acid spills and exposure to harmful fumes poses additional safety concerns for workers.
In contrast, lithium ion forklift battery safety is much higher. Lithium forklift batteries are fully sealed and do not require watering, eliminating the need for workers to handle dangerous chemicals. They also do not produce harmful emissions during charging, which means that ventilation systems and hydrogen detectors are not necessary, reducing the overall safety equipment costs. This minimizes the risk of accidents and injuries, providing a safer work environment for warehouse staff. In addition, the lower maintenance needs of lithium ion batteries reduce the chance of human error during battery handling, further enhancing safety.
3. Lithium Ion Battery Advantages in Forklift Market
The lithium ion battery advantages in forklift market are numerous, and they provide a competitive edge for businesses looking to optimize their operations. One of the key benefits is the ability to support continuous operation. Lithium forklift batteries can be opportunity charged during short breaks, allowing for multi-shift operations without the need for battery swapping or extensive downtime. This is a game-changer for warehouses that operate 24/7, as it eliminates the need to purchase and manage multiple batteries per forklift.
Another significant advantage is the energy efficiency of lithium forklift batteries. While lead-acid batteries only convert about 75% of the energy consumed during charging into usable power, lithium forklift batteries can achieve up to 99% energy efficiency. This means that almost all the energy used to charge the battery is converted into work, resulting in lower electricity costs and a more environmentally friendly operation.
In cold storage environments, lithium forklift batteries perform exceptionally well. Lead-acid batteries can lose up to 35% of their capacity in freezing temperatures, leading to more frequent battery changes and higher energy consumption. Lithium forklift batteries, on the other hand, maintain their performance even in low temperatures, ensuring reliable operation and reducing the need for frequent battery replacements in cold storage facilities.
Furthermore, the longer lifespan of lithium forklift batteries—up to four times that of lead-acid batteries—means fewer battery replacements are needed over time. This reduces not only the cost of purchasing new batteries but also the logistical challenges of storing and maintaining multiple backup batteries. With less frequent replacements, companies can lower their operational costs and reduce downtime, ultimately increasing productivity and profitability.
4. Improved Productivity
The combination of faster charging times, longer battery life, and less frequent maintenance allows companies using lithium forklift batteries to experience a significant boost in productivity. Since these batteries can charge in as little as two hours, compared to the eight-hour charging cycle required for lead-acid batteries, forklifts spend less time out of commission and more time in operation.
Additionally, lithium forklift batteries do not suffer from performance degradation as they discharge, meaning that forklifts can operate at full capacity for longer periods. Lead-acid batteries, in contrast, gradually lose power as they discharge, which can slow down forklift performance and decrease overall productivity. With lithium forklift batteries, operators can rely on consistent performance throughout their shift, ensuring that tasks are completed efficiently.
The ability to opportunity charge during breaks also means that forklifts can run continuously across multiple shifts without the need for battery swapping or charging downtime. This uninterrupted operation enables warehouses to meet tight deadlines and increase throughput, ultimately enhancing their competitive advantage in the market.
5. Boosting Operational Competitiveness
Investing in lithium forklift batteries not only improves productivity and safety but also enhances a company’s long-term competitiveness. By reducing energy costs, minimizing downtime, and lowering maintenance needs, businesses can streamline their operations and reduce overall expenses. These operational improvements allow companies to allocate resources more effectively, focus on core business activities, and deliver products to customers more quickly.
Moreover, the environmental benefits of lithium forklift batteries—such as reduced energy consumption and fewer hazardous materials—align with growing corporate responsibility initiatives. Companies that adopt lithium forklift batteries can market themselves as environmentally conscious businesses, which is becoming increasingly important in today’s market. This can attract eco-conscious customers and strengthen the company’s reputation, further boosting its competitiveness.
In conclusion, while the initial lithium forklift battery cost may be higher than traditional lead-acid batteries, the long-term benefits far outweigh the upfront investment. From improved safety and energy efficiency to increased productivity and operational competitiveness, lithium forklift batteries provide a clear advantage for businesses looking to optimize their forklift operations and achieve long-term success.
How to Evaluate Whether Lithium-Ion is Right for Your Fleet
When assessing whether lithium forklift batteries are the right choice for your fleet, it’s essential to evaluate the specific needs of your operation. Efficiency, productivity, and cost savings are key factors that determine the success of any material handling operation. Lithium forklift batteries may offer significant advantages, but they are not always the best fit for every business. Below are several important factors to consider when deciding whether to switch to lithium-ion forklift batteries.
1. Multi-Shift Operations
One of the most significant benefits of using lithium forklift batteries is their ability to support multi-shift operations. In industries such as manufacturing, third-party logistics (3PL), and food processing, forklifts often need to run continuously to meet production demands. Lithium forklift batteries can be charged quickly and efficiently, often in just one to two hours, which is a huge improvement over lead-acid batteries that require eight hours to charge and another eight hours to cool.
For businesses that operate around the clock, lithium-ion technology eliminates the need for multiple batteries per forklift. Unlike lead-acid batteries, which need frequent battery swaps to keep forklifts running, lithium forklift batteries can be opportunity charged during breaks or idle times. This means that a single battery can power a forklift for an entire day without interruption, drastically reducing downtime and increasing overall productivity.
2. Cold Storage or Freezer Environments
Another critical factor to evaluate is whether your forklifts operate in cold storage or freezer environments. Lithium forklift batteries perform significantly better than lead-acid batteries in cold conditions. Lead-acid batteries can lose up to 35% of their capacity when operating in freezing temperatures, which leads to more frequent battery replacements and higher energy costs. On the other hand, lithium-ion batteries are much more resilient in low-temperature environments, maintaining their capacity and performance even in sub-zero conditions.
For businesses operating in cold storage or freezer facilities, this increased reliability can be a game-changer. Lithium forklift batteries also charge quickly in cold environments, ensuring that forklifts can stay operational without the need for extended downtime or battery swaps. This level of performance makes lithium-ion batteries the ideal choice for companies looking to optimize their cold storage operations.
3. Profit Margins and Cost Efficiency
If your business operates with tight profit margins, every cost-saving measure counts. While lithium forklift batteries come with a higher initial cost, the long-term savings they provide can make a significant difference to your bottom line. Lithium forklift batteries are up to 40% more energy-efficient than lead-acid batteries, which directly translates to lower energy bills. They are also 88% more efficient than diesel-powered forklifts, making them a more sustainable and cost-effective option.
In addition to energy savings, lithium-ion technology requires far less maintenance than lead-acid batteries. Lead-acid batteries must be regularly watered, cleaned, and monitored for performance, which adds labor costs and increases the risk of maintenance errors. In contrast, lithium forklift batteries are virtually maintenance-free, eliminating the need for watering or equalizing charges. This reduces the time and cost spent on battery upkeep, freeing up resources for other operational priorities.
4. Productivity Demands
The ability to quickly charge lithium forklift batteries and use them for longer periods makes them an excellent choice for businesses focused on maximizing productivity. Lead-acid batteries require lengthy charging and cooling periods, which can result in significant downtime. On the other hand, lithium-ion batteries can be charged during short breaks, allowing forklifts to remain operational across multiple shifts without the need for frequent battery changes.
Opportunity charging, which is a unique feature of lithium-ion batteries, allows forklifts to charge in as little as 15 to 30 minutes during breaks. This ensures that the forklift can continue operating without interruption, even in high-demand environments. For businesses where time is of the essence, this increase in operational efficiency can provide a competitive edge.
5. Return on Investment
For many businesses, the upfront cost of lithium forklift batteries is a significant consideration. However, it’s important to look beyond the initial investment and evaluate the total cost of ownership. Lithium-ion batteries typically have a lifespan of up to 3,000 cycles, compared to 1,500 cycles for lead-acid batteries. This means that lithium forklift batteries need to be replaced less frequently, reducing long-term replacement costs.
Additionally, the reduced maintenance requirements and energy savings from lithium-ion technology can result in a return on investment (ROI) within as little as 36 months for multi-shift operations. Even for single-shift operations, the ROI can be achieved within five years, making lithium forklift batteries a cost-effective long-term solution.
6. Safety and Environmental Impact
Safety is another important factor to consider when deciding whether lithium-ion batteries are right for your fleet. Lead-acid batteries contain hazardous chemicals like sulfuric acid, which pose safety risks during maintenance and charging. The need for regular watering and cleaning increases the likelihood of accidents, such as acid spills or exposure to harmful gases.
Lithium forklift batteries, on the other hand, are sealed units that require no maintenance and do not emit harmful gases. This eliminates the need for special ventilation systems or safety equipment, such as hydrogen detectors, in the charging area. Additionally, the absence of hazardous chemicals makes lithium-ion batteries a more environmentally friendly option, reducing your company’s environmental footprint and contributing to a safer work environment.
Steps to Convert Your Forklift Fleet to Lithium Batteries
Switching your forklift fleet to lithium forklift batteries can be a straightforward process that brings numerous benefits, including improved efficiency, lower maintenance, and enhanced performance. While the conversion from lead-acid to lithium forklift batteries is not overly complicated, there are specific steps and considerations to ensure a successful transition. Below are the key steps to converting your fleet to lithium-ion batteries.
1. Assess Your Current Forklift Fleet
The first step in converting your fleet to lithium forklift batteries is to assess your current forklift models and their power needs. Since forklifts come in various types and sizes, understanding the specific requirements of each model is crucial. Start by identifying the voltage and amp-hour (Ah) rating of the lead-acid batteries you are currently using. This will help you determine the appropriate lithium forklift battery replacement that matches the energy needs of your forklifts.
2. Choose the Right Lithium Battery
Once you have assessed your fleet, the next step is selecting the right lithium forklift battery for each forklift. It’s important to choose a battery with the same voltage as your current lead-acid battery to ensure compatibility with the forklift’s electrical system. However, one of the advantages of lithium-ion technology is that it offers a wider range of amp-hour capacities, allowing you to choose a battery that better suits the energy needs of each forklift in your fleet.
Ensure that the battery capacity (measured in Ah) is sufficient for your operational requirements. Forklifts that run continuously or on multi-shift operations may require higher-capacity batteries to maximize runtime and reduce the need for frequent charging.
3. Consider Weight and Balance
Another critical consideration when converting to lithium forklift batteries is the weight difference between lead-acid and lithium-ion batteries. Lithium forklift batteries are typically much lighter than their lead-acid counterparts. For counterbalance forklifts, where the battery acts as part of the counterweight, this reduction in weight can affect the forklift’s stability and load-carrying capacity.
To compensate for the lighter weight of lithium-ion batteries, you may need to add ballast or additional counterweight to the forklift. This will ensure that the forklift maintains its rated load-carrying capacity and operates safely under normal working conditions.
4. Upgrade or Adjust Charging Equipment
Converting to lithium forklift batteries may also require changes to your charging infrastructure. While lithium-ion batteries charge faster than lead-acid batteries and can be opportunity charged during breaks, you need to ensure that your current chargers are compatible with lithium-ion technology. Most lithium forklift batteries require chargers designed specifically for lithium batteries, as they use different charging algorithms to optimize battery life and performance.
Additionally, it’s important to ensure that the charging stations are equipped with battery monitoring systems to track battery health, charge cycles, and performance. These systems help prevent overcharging or undercharging, ensuring that the batteries remain in optimal condition for longer.
5. Train Operators on Opportunity Charging
To maximize the benefits of switching to lithium forklift batteries, it’s essential to train your forklift operators on proper charging practices. One of the biggest advantages of lithium-ion batteries is their ability to be charged during short breaks without reducing the overall lifespan of the battery. This is known as opportunity charging.
Encourage your operators to take advantage of opportunity charging whenever the forklifts are idle for a few minutes or during scheduled breaks. Unlike lead-acid batteries, which degrade if charged too frequently, lithium forklift batteries can handle frequent partial charges without negatively affecting their performance or longevity. This practice ensures that your forklifts are always ready for operation, reducing downtime and increasing productivity.
6. Install Monitoring and Safety Systems
When converting to lithium forklift batteries, it’s crucial to install battery monitoring systems that can provide real-time data on battery health, charge levels, and performance. Lithium-ion batteries require precise voltage and current management to prevent overcharging or deep discharging, both of which can damage the battery.
Some monitoring systems rely on voltage-based measurements, which may not provide accurate readings for lithium forklift batteries. Instead, use shunt-based monitoring systems that track amp-hour consumption and provide more reliable data for lithium-ion batteries. This will help you maintain the batteries in peak condition and prevent unexpected failures.
7. Evaluate the Total Cost of Conversion
Although lithium forklift batteries come with a higher upfront cost compared to lead-acid batteries, the long-term savings in energy, maintenance, and replacement costs can make the investment worthwhile. It’s important to evaluate the total cost of conversion, including the cost of the batteries, potential modifications to the forklifts, and any necessary upgrades to the charging infrastructure.
In most cases, businesses see a return on investment (ROI) within 36 months, especially in high-demand, multi-shift operations. For single-shift operations, the ROI may take longer, but the lower maintenance costs and increased productivity make the investment in lithium forklift batteries a smart long-term decision.
8. Consider Future Expansion
When converting your fleet to lithium forklift batteries, it’s worth considering the scalability of your operations. Lithium-ion technology is adaptable and can support the future growth of your business. If you anticipate expanding your forklift fleet or increasing operational hours, lithium forklift batteries offer the flexibility to scale up without requiring additional batteries or significant infrastructure changes. The ability to quickly charge and opportunity charge lithium-ion batteries ensures that they can keep up with growing demands.
Conclusion
Switching to lithium forklift batteries involves more than just replacing old batteries. By following the proper steps—evaluating fleet needs, choosing the right battery, updating charging equipment, and training staff—businesses can ensure a smooth transition and enjoy the benefits of lower maintenance, increased productivity, and long-term cost savings. With the ability to opportunity charge and reduced downtime, lithium forklift batteries provide a competitive edge in today’s demanding material handling environments.
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1. Battery capacity
Table of Contents
Generally the capacity of the battery is determined by the amount of active material in the battery, usually expressed in milliampere-hour mAh or Ah. For example, 1000 mAh can be discharged for 1 h with a current of 1 A.
1.1 Understanding Battery Capacity: Rated vs. Actual vs. Theoretical
Battery capacity can be categorized into actual capacity, theoretical capacity, and rated capacity, based on different conditions.
The capacity that a battery provides when discharged at a particular discharge rate at 25°C down to its terminal voltage is defined as the battery’s capacity during design and production. This is termed the rated capacity for a given discharge rate RH.
Battery capacity is typically measured in AH (Ampere-hours). Another method of measurement is in terms of CELL (per unit plate) in watts (W/CELL).
- For Ah (Ampere-hours) calculations, you take the discharge current (constant current) I and multiply it by the discharge time (in hours) T. For instance, a 7AH battery discharged continuously at 0.35A can last for approximately 20 hours.
- The standard charging time is 15 hours, and the charging current is 1/10 of the battery’s capacity. Fast charging may reduce the battery’s lifespan.
Battery capacity refers to the size of the stored electrical charge in a battery. The unit for battery capacity is “mAh”, known in Chinese as milliampere-hours. For larger capacity batteries, such as lead-acid batteries, “Ah” (Ampere-hours) is generally used for convenience, where 1Ah = 1000mAh. If a battery has a rated capacity of 1300mAh, and you discharge the battery with a current of 130mA, the battery can operate for about 10 hours (1300mAh/130mA = 10h). If the discharge current is 1300mA, then the operational time drops to around 1 hour. These calculations assume ideal conditions, and actual device operation may vary based on components, like an LCD screen or flash in a digital camera, which can cause large variations in current. Hence, the actual operational time for a device powered by the battery can only be approximated, usually based on real-world experience.
1.2 Unit of Capacity
Typically, battery capacity is measured in ampere-hours (Ah), and this is determined for a specific battery in mind. For instance, the question might be: What’s the capacity of this smartphone battery? Or, what’s the capacity of this electric scooter battery? These queries are unique to each battery. When the battery voltage is already defined and one isn’t considering the real-time voltage, merely stating the ampere-hours can represent the battery’s capacity.
However, when dealing with batteries of different voltages, one can’t simply rely on ampere-hours to denote capacity. Take, for instance, a MANLY 12V 20AH battery and a MANLY 15V 20AH battery. Even though both have 20AH, when powering a device with the same load, the device will work just fine, but the duration of operation will differ. Hence, the standard capacity should be measured in terms of power.
To illustrate further, consider a device that can support both 12V and 24V. If powered by a MANLY 12V 20AH battery, it can last for one hour. However, if two such batteries are connected in series, resulting in 24V 20AH, the ampere-hours remain unchanged, but the operational time doubles. In this context, the capacity should be viewed in terms of the power the battery can hold, not just the ampere-hours.
Power (W) = Power (P) * Time (T) = Current (I) * Voltage (U) * Time (T).
This approach to discussing battery capacity is more meaningful. One must be realistic and factual; otherwise, you might end up with the illogical claim that a smartphone battery has a larger capacity than an electric scooter battery, which is clearly unscientific.
2. Nominal voltage
The potential difference between the positive and negative electrodes of the battery is called the nominal voltage of the battery. The nominal voltage is determined by the electrode potential of the plate material and the concentration of the internal electrolyte. The discharge diagram of lithium battery is parabolic, with 4.3V dropping to 3.7V and 3.7V dropping to 3.0V, both of which change rapidly. Only the discharge time of about 3.7V is the longest, accounting for almost 3/4 of the time, so the nominal voltage of the lithium battery refers to the voltage that maintains the longest discharge time.
- Ternary Lithium Battery
The nominal voltage of a ternary lithium cell is 3.6V, with an operating voltage range between 2.5V and 4.2V. For a battery pack, you multiply the voltage by the number of cells in series. For instance, for a 10-series ternary lithium battery pack, the nominal voltage stands at 36V, and the working voltage range spans from 25V to 42V.
- Lithium Iron Phosphate Battery
The nominal voltage of a lithium iron phosphate cell is 3.2V, with an operational voltage range of 2.0V to 3.65V. Similarly, for the corresponding battery pack, you multiply by the number of cells in series. For example, a 15-series lithium iron phosphate battery pack has a nominal voltage of 48V, with a working voltage range of 30V to 54.75V.
So, what are the implications of a low voltage for lithium batteries?
It’s recommended that lithium batteries be stored long-term with about 70% of their charge. If not in use for 3 to 6 months, it’s advisable to cycle through one full charge and discharge. This benefits the overall lifespan of the battery pack.
If stored for extended periods without use and at very low voltages, the materials in the lithium battery can be adversely affected. Their chemical reactivity might deteriorate, which in turn impacts the battery pack’s lifespan.
Lithium-ion batteries operate at voltages ranging from 2.5V to 4.2V. When the voltage drops below 2.5V, the battery discharge terminates, and due to the closing of the discharge circuit, the current loss of the internal protection circuit drops to its lowest. However, in real-world applications, due to variations in internal materials, the discharge termination voltage can range from 2.5V to 3.0V. When the voltage exceeds 4.2V, the charging circuit is terminated to ensure the battery’s safety.
3. Charge termination voltage
When the rechargeable battery is fully charged, the active material on the electrode plate has reached a saturated state, and the battery voltage will not rise when the battery continues to be charged. The voltage at this time is called the end-of-charge voltage. The ternary lithium battery is 4.2V, and the lithium iron phosphate battery is 3.65V.
4. Discharge termination voltage
The end-of-discharge voltage refers to the lowest voltage allowed when the battery is discharged. The discharge termination voltage is related to the discharge rate.
5. Internal resistance of the battery
The internal resistance of the battery is determined by the resistance of the electrode plate and the resistance of the ion flow. During the charging and discharging process, the resistance of the image engine and the electrode plate is unchanged, but the resistance of the ion flow will increase or decrease with the concentration of the electrolyte and the charged ions. And change. When the OCV voltage of a lithium battery decreases, the impedance will increase. Therefore, when charging at low power (less than 3V), pre-charge (trickle charging) must be carried out first to prevent too much current from causing excessive heat generation of the battery.
Composition of Lithium Battery Internal Resistance
Ohmic resistance mainly arises from the electrode materials, electrolyte, separator resistance, as well as the contact resistance of current collectors and tab connections. It’s related to the battery’s size, structure, and connection methods.
Polarization resistance, which emerges instantly when current is applied, represents the cumulative tendency of various barriers inside the battery preventing charged ions from reaching their destinations. This resistance can be further categorized into electrochemical polarization and concentration polarization.
Currently, the standout 18650 lithium battery has an internal resistance of around 12 milliohms, while typical ones hover between 13 to 15 milliohms. Given that impedance can affect the battery’s performance, generally speaking, 50 milliohms is deemed normal. Between 50 to 100 milliohms, the battery remains functional, but performance starts to degrade. When exceeding 100 milliohms, parallel use is necessary, and anything above 200 milliohms is virtually unusable.
Impacts of Lithium Battery Internal Resistance
All factors that impede the movement of lithium ions and electrons from one pole to another within the lithium battery contribute to its internal resistance. Ideally, the lower the internal resistance, the better. A higher internal resistance leads to increased thermal losses, preventing high current discharge. Moreover, a high internal resistance means the battery heats up during use. Elevated temperatures can cause the battery’s discharge operating voltage to drop and its discharge duration to shorten, severely affecting battery performance and lifespan. In extreme cases, this can even pose a risk of spontaneous combustion.
6. Self-discharge rate
It refers to the percentage of the total capacity that is automatically lost when the battery is not in use for a period of time. Generally, the self-discharge rate of lithium-ion batteries at room temperature is 5%-8%.
6.1 How Does the Discharge Rate Affect Battery Capacity?
The discharge rate directly impacts a battery’s effective capacity. Specifically, a higher discharge rate can decrease the available capacity, as the battery might not be able to maintain its maximum rated capacity during rapid discharges. Thus, when evaluating a battery’s usable capacity, the discharge rate must be taken into account.
6.2 What is the Discharge Rate of Electric Bicycle Batteries?
The discharge rate of electric bicycle batteries can vary based on the specific battery chemistry and design. Electric bikes typically employ lithium-ion batteries due to their high energy density and performance. These batteries generally demonstrate a discharge rate ranging from 1C to 4C or even higher. To illustrate, a 1Ah battery with a 10C discharge rate can deliver a continuous discharge current of 10 amps, whereas a 4C rate would allow for a continuous discharge current of 40 amps.
6.3 What is Considered a High Discharge Rate for Lithium Batteries?
For lithium batteries, a discharge rate typically considered “high” starts at 1C and above. However, it’s important to note that what’s deemed as a high specific discharge rate may vary based on the battery’s design, chemical composition, and intended application.
6.4 What is a Good Discharge Rate for Batteries?
An optimal C-rate for a battery hinges on the specific demands of its application. Typically, a discharge rate that facilitates efficient power transfer without overly stressing the battery is regarded as favorable. It’s recommended to consult the manufacturer’s specifications and guidelines to ascertain the best discharge rate for a particular battery.
6.5 How Do You Calculate the C-rate?
C-rate (C) = Charging or discharging current in amperes (A) / Battery’s rated capacity (Ah)
Let’s delve into an example involving a 100Ah lithium battery:
1C represents a discharge current of 100 amps, meaning the battery can provide a continuous discharge of 100 amps for one hour. In simpler terms, it can handle a load current of 100 amps for 60 minutes.
If we boost the C-rate to 2C, the discharge current becomes 200 amps. This signifies that the battery can now furnish a discharge current of 200 amps, but for a reduced duration. At a 2C rate, the battery can sustain a load current of 200 amps for 30 minutes or half an hour.
On the other hand, reducing the C-rate to 0.5C results in a discharge current of 50 amps. At a 0.5C rate, the battery can deliver a discharge current of 50 amps, thereby prolonging the discharge period. Under these conditions, the battery can support a load current of 50 amps for 2 hours or 120 minutes.
When assessing the performance and capacity of lithium batteries, the C-rate stands out as a crucial factor since it determines both the available discharge current and the corresponding discharge duration.
The reason why lithium batteries need protection is determined by their own characteristics. Since the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short circuited, and ultra-high temperature charge and discharge, the lithium battery components of the lithium battery will always appear with an exquisite protection board.
Ordinary lithium battery protection boards usually include control ICs, MOS switches, resistors, capacitors and auxiliary devices FUSE, PTC, NTC, ID, memory, etc. Among them, the control IC controls the MOS switch to turn on under all normal conditions to make the cell and the external circuit conduct, and when the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the cell’s Safety.
When the protection board is normal, Vdd is high, Vss and VM are low, DO and CO are high. When any parameter of Vdd, Vss, VM is changed, the level of DO or CO will be Changes.
1. Overcharge detection voltage: Under normal conditions, Vdd gradually rises to the voltage between VDD and VSS when the CO terminal changes from high level to low level.
2. Overcharge release voltage: In the charging state, Vdd gradually decreases to the voltage between VDD and VSS when the CO terminal changes from low level to high level.
3. Overdischarge detection voltage: Under normal conditions, Vdd gradually decreases to the voltage between VDD and VSS when the DO terminal changes from high level to low level.
4. Overdischarge release voltage: In the overdischarge state, Vdd gradually rises to the voltage between VDD and VSS when the DO terminal changes from low level to high level.
5. Overcurrent 1 detection voltage: Under normal conditions, VM gradually rises to the voltage between VM and VSS when DO changes from high level to low level.
6. Overcurrent 2 detection voltage: In the normal state, VM rises from OV to the voltage between VM and VSS when the DO terminal changes from high to low at a speed of 1ms or more and 4ms or less.
7. Load short-circuit detection voltage: Under normal conditions, VM starts from OV and rises to the voltage between VM and VSS when the DO terminal changes from high level to low level at a speed of 1μS or more and 50μS or less.
8. Charger detection voltage: In the over-discharge state, VM gradually decreases with OV to the voltage between VM and VSS when DO changes from low level to high level.
9. Current consumption during normal operation: Under normal conditions, the current (IDD) flowing through the VDD terminal is the current consumption during normal operation.
10. Over-discharge current consumption: In the discharging state, the current (IDD) flowing through the VDD terminal is the over-current discharge current consumption.
Lithium iron phosphate batteries generally consist of a positive electrode, a negative electrode, a separator, an electrolyte, a casing and other accessories.
The positive electrode active material is olivine-type lithium iron phosphate (LiFePO4), which can only be used after modification such as carbon coating and doping.
The negative electrode active materials are graphite materials such as natural graphite and artificial graphite, as well as carbon materials such as hard carbon and soft carbon, which also require proper treatment before they can be used.
The diaphragm is one or two of polyethylene (PE) and polypropylene (PP). It is often used as a single-layer or multi-layer composite film. There are also ways to increase the inorganic ceramic film on the surface of the film. To a certain extent Improve battery safety.
The electrolyte is a lithium salt solution with chain or cyclic carbonate as the solvent, and special additives are added to it.
The outer shell is a container that contains the other components of the battery. It is mostly made of high-strength, corrosion-resistant stainless steel, aluminum alloy, special plastics and other materials. There are also batteries with aluminum-plastic composite film as the outer shell. In actual use, a high-strength outer shell is needed for protection. .
In addition, there are conductive agents that increase the conductivity of the positive and negative electrodes in the battery, the binder that fixes the active material, the copper foil and aluminum foil that support the powder material and the current collector, and connect the inside and outside of the battery and the conductive connecting piece, Auxiliary accessories such as tabs and poles.
